ADJUSTMENT AND CLEANING OF 9N3979
FUEL INJECTION NOZZLES
NOTE: Do not clean or adjust a nozzle with a valve
opening pressure (VOP) less than 1500 psi (10300 kPa).
Valve Opening Pressure (VOP) Adjustment
FUEL INJECTION NOZZLE
1. Fuel injection nozzle. 2.Locknut (for
pressure adjust- m., lt screw). 3. Pressure
adjustment screw. 4. 1H1023 O-ring Seal for
cap. 5. Locknut (for lift adjustment screw).
6. Lift adjustment screw.
1. Remove fuel injection nozzle (I) from
the5P4150 Nozzle Tester and put it in the
8S2250 No771e Holding Tool (P).
1. Fuel injection nozzle. 7.8H8502 Combination
P. 8S2250 Nozzle Holding Tool.
2..Loosen locknut (5) that holds lift adjustment
screw (6). Turn lift adjustment screw (6)
counter clock wise two turns.
If the lift adjustment screw is not turned counter
clock wise two turns, the valve can be bent or
the seat for the valve can be damaged when the
pressure adjustment screw is turned.
3. Hold lift adjustment screw (6) with a 5, 64" hex
wrench (8) and remove lock nut (5).
5. Locknut (for lift adjustment screw). 8. 5/64" hex
1. Fuel injection nozzle. 9. 8H8505 Combination
4. Loosen lock nut (2) that holds pressure adjustment
5. Put fuel injection nozzle (I) on the nozzle tester. Turn
pressure adjustment screw (3) clockwise with 5P4813
Socket (10). Each one- fourth of a turn will increase
the opening pressure approximately 250 psi (1720